I-V anomalies on InAlAs/InGaAs/InP HFETs and deep levels investigations

In this paper, static measurements and defect analysis performed on InAlAs/InGaAs/InP HFETs are presented. Id-Vds-T, Id-Vgs-T and Ig-Vgs-T characteristics show anomalies (leakage current, degradation in saturation current, kink effect, distortions on Id-Vd characteristics in saturation region after high voltage application, …). Deep defects analysis performed by means of capacitance transient spectroscopy (C-DLTS) and frequency dispersion of the output conductance (Gds(f)) prove the presence of deep defects with activation energies ranging from 0.12 to 0.75 eV. The presence of generation-recombination centers, acting like traps, is confirmed by Ig-Vgs. The localization and the identification of these defects are presented. Finally, the correlation between the anomalies observed on output characteristics and defects is discussed.